CN109936398A - System and method for testing the wireless device with beamforming circuitry - Google Patents

Abstract

Disclosed herein are systems and methods for testing wireless devices having beamforming circuitry (106). An example system includes a shielded test enclosure (110), a wireless channel emulator (115), and a test instrument (120). The shielded test enclosure (110) provides a cableless connection between the wireless device and the wireless channel emulator (115), thereby allowing testing of various types of wireless devices, especially wireless devices without radio frequency (RF) connectors. The shielded test enclosure (110) is smaller and less expensive than conventional multi-probe anechoic chambers. In one exemplary application, a shielded test enclosure (110) is used to house a multiple-input multiple-output (MIMO) antenna array and a probe antenna array (112) of a wireless device. The probe antenna array (112) is coupled to the wireless channel emulator (115) and used to receive signals from MIMO antenna arrays of various sizes, thereby eliminating the need to uniquely customize the probe antenna array (112) for any particular MIMO antenna array (111) ).

Description

System and method for testing wireless devices with beamforming circuitry

Background technique

Wireless devices are ubiquitous in our daily lives. For example, it is difficult for the average person to get through a day without using a cell phone. The proliferation of such wireless devices has created an ever-increasing demand for bandwidth and services. Increases in bandwidth are often obtained by using higher and higher frequencies, as illustrated by the evolution of third-generation (3G) wireless industry standards to fourth-generation (4G) and fifth-generation (5G) wireless industry standards at this point. Especially in terms of reducing the size of wireless devices, the increase in frequency bandwidth is often accompanied by changes in hardware.

The reduction in size is achieved, at least in part, by eliminating radio frequency (RF) connectors in wireless devices. However, eliminating RF connectors in wireless devices presents challenges when they must be tested during manufacture or during subsequent use. One conventional solution for testing wireless devices involves placing the wireless device in a multi-probe anechoic chamber (MPAC) and performing over-the-air testing of the wireless device inside the MPAC. Typical MPAC chambers are expensive and large in size. For example, MPACs used to test Long Term Evolution (LTE) base stations or wireless user equipment (UE) can require a footprint in excess of 100 square meters and can be very expensive. Accordingly, it is desirable to provide a smaller and more cost-effective test system that can be used to test wireless devices.

SUMMARY OF THE INVENTION

According to an exemplary embodiment of the present disclosure, a system includes a probe antenna array, a wireless channel emulator, a device under test (DUT), a shielded test enclosure, and a test instrument. The wireless channel emulator is coupled to the probe antenna array. The DUT includes beamforming circuitry and a multiple-input multiple-output (MIMO) antenna array. The MIMO antenna array is configured to transmit one or more radio frequency signals provided by the beamforming circuit. The shielded test enclosure provides a cableless connection between the wireless channel emulator and one or more antenna ports of the DUT, and is configured to house at least the MIMO antenna array and the probe antenna array. The probe antenna array is arranged to receive one or more radio frequency signals transmitted by the MIMO antenna array. The test instrument is coupled to the wireless channel emulator and is configured to evaluate one or more beam states of the DUT based on one or more beam states utilized by the beamforming circuit to transmit the one or more radio frequency signals from the MIMO antenna array a performance characteristic.

According to another exemplary embodiment of the present disclosure, a system includes a device under test (DUT), a probe antenna array, a shielded test enclosure, and a wireless channel emulator. The DUT is coupled to a multiple-input multiple-output (MIMO) antenna array. The shielded test enclosure is configured to accommodate the MIMO antenna array and the probe antenna array. The wireless channel simulator is coupled to the probe antenna array and is configured to simulate the wireless channel by utilizing at least one or more beam states applied to one or more radio frequency signals received by the probe antenna array from the MIMO antenna array A cableless connection between the emulator and one or more antenna ports of the DUT.

According to yet another exemplary embodiment of the present disclosure, a method includes placing a MIMO antenna array in a shielded test enclosure, the MIMO antenna array coupled to a beamforming circuit of a device under test (DUT); utilizing the shielded test enclosure housing the MIMO antenna array and the probe antenna array; determining a set of transfer functions between the MIMO antenna array and the probe antenna array for a set of beam states used by the beamforming circuit using a wireless channel emulator; utilizing the wireless channel The simulator simulates the interaction of the wireless channel simulator with the DUT by applying one or more calibration coefficients determined using the set of transfer functions to one or more radio frequency signals propagating between the MIMO antenna array and the probe antenna array. a cableless connection between one or more antenna ports; and utilizing the cableless connection to evaluate one or more performance characteristics of the DUT.

Other embodiments and aspects of the present disclosure will become apparent from the following description taken in conjunction with the accompanying drawings.

Description of drawings

Many aspects of the present invention may be better understood by reference to the following description, taken in conjunction with the appended claims and accompanying drawings. The same reference numerals refer to the same structural elements and features in the various figures. For the sake of clarity, not every element will be labeled with a reference numeral in every drawing. The drawings are not necessarily to scale; emphasis instead is placed upon illustrating the principles of the invention. The drawings should not be construed to limit the scope of the invention to the exemplary embodiments shown herein.

1 illustrates an exemplary test system including a shielded test enclosure that provides a cableless connection between a device under test and a wireless channel emulator, according to an exemplary embodiment of the present disclosure.

FIG. 2 shows the RF signal path inside the shielded test enclosure shown in FIG. 1 .

Figure 3 shows a symbolic representation of an exemplary test system in which the cableless connections provided by the shielded test enclosure are hypothetically replaced with cables.

4 illustrates a symbolic representation of an exemplary test system including a shielded test enclosure in accordance with an exemplary embodiment of the present disclosure.

5 illustrates another exemplary test system including a wireless channel emulator wirelessly coupled to a test instrument in accordance with another exemplary embodiment of the present disclosure.

6 illustrates an exemplary flow diagram of a method of testing a device having a beamforming circuit in accordance with an exemplary embodiment of the present disclosure.

Detailed ways

In this specification, embodiments and variations are described for the purpose of illustrating uses and implementations of the inventive concepts. The illustrative descriptions should be understood to present examples of inventive concepts, rather than to limit the scope of the concepts disclosed herein. For this purpose, certain words and terms as used herein are for convenience only, and such words and terms should be broadly construed to include various forms and equivalents commonly understood by those of ordinary skill in the art purpose and action. For example, it should be understood that the word "coupled" as used herein in one context may refer to a communicative coupling between two elements, such as the transfer of signals from one element to another (either wirelessly or through a wired medium), and A mechanical connection, such as a coaxial cable between two elements, may be indicated in a different context. As another example, the term "propagate" as used herein generally refers to a signal passing through an object or through free space. As yet another example, the phrase "configured to" as used herein generally refers to an object having the physical structure and/or ability to perform the action described in the context of the phrase. It is also to be understood that words such as "exemplary" and "exemplary" as used herein are non-exclusive and non-limiting in nature. More specifically, the word "exemplary" as used herein indicates one of several examples, and it should be understood that no special emphasis, exclusivity or preference is associated or implied by use of this word. Additionally, it may be noted that while certain examples provided below for descriptive purposes may indicate that signals propagate through various elements in a right-to-left direction, it should be understood that the description may equally apply to signals passing through These elements propagate in a left-to-right direction.

Generally, according to various illustrative embodiments disclosed herein, a system for testing a wireless device with beamforming circuitry includes a shielded test enclosure, a wireless channel emulator, and a test instrument. The shielded test enclosure provides a cable-free connection between the wireless device and the wireless channel emulator, thereby allowing testing of various types of wireless devices, especially those without radio frequency (RF) connectors. Compared to traditional multi-probe anechoic chambers, this shielded test enclosure is smaller and less expensive. The smaller size can be attributed to various factors such as the higher operating frequency of the wireless device and the elimination of certain items such as RF absorbing materials. In one exemplary application, the shielded test enclosure is used to house multiple-input multiple-output (MIMO) antenna arrays and probe antenna arrays for wireless devices. The probe antenna array is coupled to the wireless channel emulator and used to receive signals from MIMO antenna arrays of various sizes, thereby eliminating the need to uniquely customize the probe antenna array for any particular MIMO antenna array.

FIG. 1 shows an exemplary test system 100 including a shielded test enclosure 110 , a device under test (DUT) 105 and a wireless channel emulator 115 . According to various exemplary embodiments of the present disclosure, shielded test enclosure 110 provides a cableless connection between DUT 105 and wireless channel emulator 115 . DUT 105 may be any of various types of wireless devices, such as personal communication devices, communication devices used by service providers, and consumer entertainment devices. An example of a personal communication device is a cellular device such as a smartphone. Some examples of communication devices used by service providers include Long Term Evolution (LTE) base stations, wireless user equipment (UE), or various other types of communication devices operating in the mm wavelength region. Some examples of consumer entertainment devices include Sony or Microsoft

Test instrument 120 may be any of various types of test instruments, such as a Keysight wireless communication test set or a Keysight performance vector signal analyzer. In some example implementations, the test instrument 120 may be an LTE base station or UE, a 5G base station or UE, or any other device operating in the mm wavelength region. The DUT 105 may be a communication device configured to communicate with the test instrument 120 to perform various types of tests to evaluate the performance characteristics of the test instrument 120 (LTE base station or UE). In some other exemplary implementations, the test instrument 120 initiates a test procedure by communicating with the DUT 105 to test the DUT 105 . In some other exemplary implementations, the DUT 105 may initiate a self-test process and use the test instrument 120 to perform the self-test of the DUT 105 . Test procedures may be performed to evaluate various downlink and uplink performance characteristics of the DUT 105, such as downlink and uplink throughput performance, downlink and uplink signal characteristics, and for evaluating baseband parameters.

DUT 105 includes beamforming circuitry 106 for providing radio frequency signals to an antenna array such as MIMO antenna array 111 placed inside shielded test enclosure 110 . In some cases, the MIMO antenna array 111 is an integral part of the housing of the DUT 105 , so the DUT 105 is placed inside the shielded test enclosure 110 . In some other cases, MIMO antenna array 111 is a stand-alone component that is placed in shielded test enclosure 110 and coupled to DUT 105 via a set of "N" communication links 107 .

Processor 104 is coupled to beamforming circuit 106 and is used to configure beamforming circuit 106 to provide drive signals to MIMO antenna array 111 . The drive signal is typically generated in beamforming circuit 106 by using beamforming techniques that involve the use of two variables: amplitude and phase. The combination of these two variables is used to improve sidelobe suppression and/or steering nulls in order to configure the MIMO antenna array 111 to radiate directional RF signals.

Various beamforming techniques that may be used by beamforming circuitry 106 include analog beamforming, digital beamforming, and hybrid beamforming. Accordingly, the beamforming circuit 106 would correspond to an analog beamforming circuit, a digital beamforming circuit, or a hybrid beamforming circuit. Analog beamforming typically involves the use of multiple analog phase shifters and multiple RF switches coupled to the RF signal chain. While the hardware can be inexpensive, implementing multi-stream RF transmission with analog beamforming can be a very complex process. Digital beamforming addresses some of the disadvantages associated with analog beamforming by using multiple RF signal chains and digital processing techniques for phase adjustment. However, due to factors such as high complexity, high cost, and high power consumption (especially in consumer devices such as cell phones), digital beamforming may not necessarily be optimal for use in certain applications. Hybrid beamforming is the proposed solution, which combines the advantages of analog beamforming and digital beamforming while addressing certain disadvantages such as complexity and cost.

In the exemplary test system 100 shown in FIG. 1 , the DUT 105 is located outside of a shielded test enclosure 110 and a set of "N" communication links 107 for connecting data from the DUT 105 The "N" drive signals are coupled to the MIMO antenna array 111 placed inside the shielded test enclosure 110. The "N" RF signals radiated by MIMO antenna array 111 are received by probe antenna array 112 , which is also located inside shielded test enclosure 110 .

According to various embodiments of the present disclosure, shielded test enclosure 110 provides a cableless connection between DUT 105 and wireless channel emulator 115 . The cableless connection eliminates the need to provide RF connectors on the DUT 105 for testing. Furthermore, the number "K" of antenna elements installed in the probe antenna array 112 (where K > N) may be large enough to accommodate various types of DUTs, and only a subset of the "K" antenna elements may be used from each A MIMO antenna array of one size can receive signals, thereby eliminating the need to change the number of antenna elements of the probe antenna array 112 to match a particular MIMO antenna array.

Thus, in a first exemplary application, DUT 105 may be a device that utilizes only 2 beam states simultaneously at any given moment, and in a second exemplary application, DUT 105 may be a device that utilizes 8 beam states simultaneously at any other moment Beam state device. The probe antenna array 112 is thus agnostic to the type of MIMO antenna array used, and operates in the beam domain (based on beam state) rather than the antenna element domain (based on antennas) according to various embodiments of the present disclosure number of components).

Conventional test systems operating in the antenna element domain will typically embody a 1:1 ratio between the number of antenna elements of the antenna array that is part of the device under test and the number of antenna elements of the probe antenna array. The 1:1 ratio also applies to the number of antenna elements of the probe antenna array to the number of channels used by the wireless channel emulator coupled to the probe antenna array.

The use of beam domain techniques not only allows the size and cost of the shielded test enclosure 110 to be reduced by using ratios other than 1:1, but also reduces the complexity and cost of the wireless channel emulator 115 compared to conventional practice. The reduction in the number of emulator channels also translates into a reduction in processing requirements on the wireless channel emulator 115 compared to conventional wireless channel emulators.

The size of the shielded test enclosure 110 is significantly smaller than that of a conventional MPAC. For example, when DUT 105 is a device operating at approximately 2.6 GHz, the interior dimensions of shielded test enclosure 110 are approximately 0.3 meters by 0.52 meters by 0.52 meters. If used inside the shielded test enclosure 110, an additional 0.2 meters may be reserved (but not required) for RF absorbing material. Thus, the overall dimensions of the shielded test enclosure 110 are equal to 0.7 meters by 0.92 meters by 0.92 meters or approximately 0.6 cubic meters. For higher test frequencies, the size can be further reduced. Due to the small size of the shielded test enclosure 110 , the probe antenna array 112 is automatically located in the near field region (ie, the Fresnel region) of the MIMO antenna array 111 . However, in other embodiments, the size of the shielded test enclosure 110 may be enlarged to allow the probe antenna array 112 to be placed in the far field region of the MIMO antenna array 111 when the power level of the signal transmitted by the MIMO antenna array 111 is high middle.

Wireless channel emulator 115 (which may also be referred to as a fading emulator) is coupled to probe antenna array 112 via a set of "K" communication links 108 and is used to simulate the absence of cables between MIMO antenna array 111 and probe antenna array 112 connect. Wireless channel emulator 115 is also coupled to test instrument 120 to provide "M" emulator channels (x ₁ (t) to x _M (t)) to test instrument 120 at various times. The operation and functionality of these "M" emulator channels are described in more detail below. In some exemplary embodiments, wireless channel emulator 115 and test instrument 120 may be housed within a single housing 125 . When housed inside a single housing 125, some of the functions of wireless channel emulator 115 and test instrument 120 may be performed by shared components such as a processor or memory.

FIG. 2 shows the RF signal path inside the shielded test enclosure 110 between the MIMO antenna array 111 and the probe antenna array 112 . DUT 105 transmits "N" signals to probe antenna array 112 using MIMO antenna array 111 . The "N" signals carried by the "N" beams of MIMO antenna array 111 are received by each of the "K" antenna elements of probe antenna array 112 and coupled into wireless channel emulator 115 .

The wireless channel simulator 115 simulates the radio frequency signal path by generating a simulated MIMO channel model. To this end, the wireless channel simulator 115 determines a set of transfer functions between the MIMO antenna array 111 and the probe antenna array 112, and optimizes various calibration matrices to be applied to various beam indices. The calibration matrix is then applied to simulate the cableless connection between the MIMO antenna array 111 and the probe antenna array 112 in real time by transmitting signals between the MIMO antenna array 111 and the probe antenna array 112 using various beam indices. The simulated cableless connection conditions the simulated MIMO channel model that can be utilized, for example, in measuring the downlink and/or uplink throughput performance of the DUT 105, and the wireless channel simulator 115 can be viewed. is a time-varying filter that convolves the input signal by using the channel impulse response of the MIMO channel model.

FIG. 3 shows a symbolic representation of the exemplary test system 100 when the cableless connections provided by the shielded test enclosure 110 are hypothetically replaced with a set of cables 310 . 4, on the other hand, shows a symbolic representation of an exemplary test system 100 in which a shielded test enclosure 110 provides cable-free connections in accordance with various embodiments of the present disclosure.

In the symbolic representation shown in FIG. 3 , test instrument 120 , which may be a user equipment (UE) or a cellular base station, performs by transmitting a signal (as indicated by signal path 305 ) to shielded test enclosure 110 via wireless channel emulator 115 Testing process. In one exemplary implementation, one fixed beam state per port is used to transmit the signal for all times. In another exemplary implementation, multiple beam states are used to transmit signals at various times. DUT 105 receives the signal from shielded test enclosure 110 and responds by transmitting the signal back to test instrument 120 . For descriptive purposes, signals transmitted by test instrument 120 to DUT 105 are referred to in this example as uplink signals, while signals transmitted by DUT 105 to test instrument 120 are referred to as downlink signals.

The wireless channel emulator 115 convolves the signals x ₁ (t) through x _M (t) provided by the test instrument 120 by using the channel impulse response h(t,τ). Convoluted signals y ₁ (t) through y _N (t) are coupled into DUT 105 via shielded test enclosure 110 . The system function can be represented by the following formula:

where n=1, 2...N and m=1, 2...M.

If delay and/or frequency domain properties are ignored for notation simplicity, equation (1) can be rewritten as follows:

Y _N×1 (t)=H _N×M (t)X _M×1 (t) (2)

where "H" represents the time-varying MIMO channel impulse response (CIR) of "M" transmitters and "N" receivers. Equation (2) defines the manner in which the wireless channel emulator 115 uses the set of cables 310 to represent the interconnection between the wireless channel emulator 115 and the DUT 105 .

Conversely, the cableless connection provided by the shielded test enclosure 110 shown in FIG. 4 can be represented by the following equation (signal flow indicated by signal path 405):

Y _N×1 (t)=F _N×K (u)G _K×N (u)H _N×M (t)X _M×1 (t) (3)

where F _N×K (u) represents the time-varying transfer function or one of the time-invariant transfer functions of the shielded test enclosure 110 , and G _K×N (u) represents the free Calibration matrix for cable connections. When the number of beam states is equal to 1, the time-invariant transfer function in the specific version is applicable. The calibration matrix is also time-varying when the beam state exceeds 1.

time "u" is equal to where "t" represents time, and " _TS " is the discrete time step between the various beam states, and Represents a round-unround (round down) operator. The terms G(u)H(t) are CIR-related parameters for the modified simulation performed by the wireless channel emulator 115 . In this exemplary description, matrix F is time-varying because beamforming circuit 106 uses analog beamforming, where each subset of antenna elements of MIMO antenna array 111 is coupled to a corresponding port of beamforming circuit 106 . Thus, the DUT 105 can change the beam shape of the signal transmitted by the MIMO antenna array 111 in a time-varying manner at each time instant "u".

Ideally, the calibration matrix G(u) is determined such that This may not be possible in practice. Accordingly, the following describes the testing process that can be performed on the testing system 100 to obtain the best solution.

Step 1. Place the MIMO antenna array 111 inside the shielded test enclosure 110 . Before placing the MIMO antenna array 111 inside the shielded test enclosure 110 , the test system 100 , particularly the shielded test enclosure 110 coupled to the wireless channel emulator 115 , can be calibrated at the center frequency of interest. The center frequency of interest may correspond to the operating frequency of the DUT 105 .

Step 2. For each of n=1, 2...N, b=1, 2,...B, k=1, 2,...K, measure from the nth antenna port of the MIMO antenna array 111 to The transfer function γ _nbk (f) of the b-th beam of the k-th antenna port of the probe antenna array 112 . This operation may be performed by enabling/disabling the antenna ports of the beamforming circuit 106 in the DUT 105 and by sequentially switching all fixed beams supported via each antenna port. In some applications, the DUT 105 may perform this operation automatically, while in some other cases, specific testing procedures may be performed for this purpose. The transfer function measurement process may be performed, for example, by enabling a first antenna port of MIMO antenna array 111 , disabling a set of remaining antenna ports of MIMO antenna array 111 , and transmitting a first radio frequency signal from the first antenna port of MIMO antenna array 111 . The transfer function measurement process can be repeated similarly for other antenna ports of the MIMO antenna array 111 .

Various types of RF test signals can be used for the transfer function measurement process. In an exemplary implementation, known pilot signals, such as cell-specific reference signals in LTE, are transmitted by DUT 105 and received and decoded by wireless channel emulator 115 . As part of the transfer function measurement process, the following formula is used to synthesize the vector:

The measurement of the complex transfer function γ _nbk (f) may be performed by the wireless channel emulator 115 once at the beginning of the DUT evaluation test process, repeatedly during the DUT evaluation test process, and/or intermittently during the DUT evaluation test process. In one or more exemplary implementations, transfer function measurements may be performed by utilizing known signal parameters used by DUT 105 . For example, wireless channel emulator 115 may down-convert and sample downlink signals received from DUT 105 . The down-converted and sampled signal can be used for synchronization, detection and decoding to determine signal parameters present in the downlink signal and then estimate the wireless channel transfer function. Estimation can be performed in various ways, such as in a handset using a known sequence of pilot tones of the DUT 105 .

The pilot tone sequences are typically orthogonal between the different antenna ports of the DUT 105, eg, by transmitting pilot symbols for each antenna port on non-overlapping time-frequency slots. The complete time-frequency wireless channel transfer function for each antenna port can then be extracted by interpolation. In this exemplary embodiment, measurements are performed at each antenna port k of the probe antenna array 112, and an estimation of the wireless channel transfer function is performed for each DUT antenna port n and beam b to obtain N×K×B The complete set of wireless channel transfer functions. Each element (n, k) of the complex transfer function includes the response of beamforming circuit 106 and one or more RF chains (not shown) with respect to each beam b of port n; each antenna element of MIMO antenna array 111 Time-invariant propagation channel between n and antenna element k of probe antenna array 112; the response of each antenna element k of probe antenna array 112; possible cables and switches between probe antenna array 112 and wireless channel emulator 115 ; and the input port RF chain response of the wireless channel emulator 115.

In the event that known pilot sequences are not available, DUT 105 may be configured to transmit known calibration sequences from each antenna port of MIMO antenna array 111 . In one exemplary implementation, the calibration sequences are transmitted simultaneously via each antenna port of the MIMO antenna array 111 and received simultaneously by the antenna ports of the probe antenna array 112 . Simultaneous transmit and receive enables fast calibration measurements.

Although the transfer function γ _nbk (f) is frequency dependent, it can be assumed that the variation of the signal amplitude within the frequency bandwidth of interest is negligible, thus allowing the frequency term to be omitted thereafter. In an example implementation where the DUT 105 is a base station with 8 ports (N=8) and the maximum number of beams per port is 56 (B=56), the total number of beams would be NxB=448. If the probe antenna array 112 contains 16 probes (K=16), a total of 7168 transfer function measurements (N×B×K=7168) can be performed.

The correlation between the vector Γ _nb of Equation (4) and the matrix F _N×K (u) of Equation (3) can be as follows: Each moment “u” of the matrix F _N×K (u) is defined by the row Γ _nb (n= 1,...,N) where for each row (ie, each port of the DUT 105) a specific beam "b" is valid

Step 3. The optimization step of the wireless channel emulator 115 is performed. Find the best weight vector for each port "n" and beam "b" maximize the channel gain |g _nb Γ _nb | and all other channel gains minimize, that is,

Any suitable optimization method can be utilized. Additional constraints can be set for optimization, such as minimum acceptable level V ₁ <|g _nb Γ _nb | and minimum ratio Finally, the determined weight vector g _nb is scaled such that

Step 4. Obtain the information of the DUT beam index vector

β(u)=[b ₁ (u),...,b _N (u)]∈{1,...,B} (7)

For each port "n", at time where "t" is time and Ts is the discrete time step between beam state updates. A different beam state may be defined for each time step "u", or the same beam state may be repeated multiple times depending on the configuration of the test system 100 . When the DUT 105 is a base station, the analog beams may be updated based on Orthogonal Frequency Division Multiplexing (OFDM) symbols.

Beamforming circuitry 106 may use multiple beam states to create multiple signals provided to MIMO antenna array 111 . Each of these beam states can be identified by a corresponding "beam index". Thus, equation (7) represents "N" beams with "B" beam indices at different instants "u". Each "beam state" or "beam index" provides a way of characterizing the RF signals transmitted by the MIMO antenna array 111 .

Step 4 can include two sub-steps:

Sub-step 4a. Synchronization method: Frame/symbol synchronization may be performed by the wireless channel emulator 115 once at the beginning of the DUT evaluation test process, repeatedly during the DUT evaluation test process, and/or intermittently during the DUT evaluation test process. In one or more exemplary implementations, the evaluation test process may be performed by utilizing known signal parameters used by DUT 105 . For example, wireless channel emulator 115 may down-convert and sample downlink signals received from DUT 105 . The down-converted and sampled signal can then be used for synchronization, detection and decoding to determine signal parameters present in the downlink signal, followed by frame and symbol synchronization extraction. In alternative implementations in which decoding beam state information is not required, synchronization may be via a trigger signal transmitted by DUT 105 and/or test instrument 120 .

Sub-step 4b. Alternative method to obtain beam state information:

1. Known fixed beam sequence :

In some example implementations, the beam state sequence may be fixed and pre-configured. Therefore, the beam state information β(u) is known a priori and does not need to be detected.

2. Dynamically scheduled beam sequence with beam sequence decoding:

The beam state information β(u) may be obtained by detecting and decoding downlink control information (DCI) or other control information that provides the beam index to the symbol index mapping information. Beam scheduling information is typically signaled 1 to 20 subframes in advance, so decoding is typically performed substantially in real time.

3. Dynamically scheduled beam sequences with sequence information signaled through the communication interface :

A dedicated communication interface for testing may be established between DUT 105 and test instrument 120 to provide beam state information β(u).

Step 5. By knowing the beam state information β(u) and the weight vector, form the following calibration matrix at time "u":

The wireless channel emulator 115 continuously constructs the MIMO channel impulse matrix over time "t" to convolve with the input signal vector X(t) as follows:

H′ ^(t) = G(u)H(t). (9)

Step 6. Wireless channel simulation and evaluation of the performance characteristics of the DUT 105 can now be performed. This may include one or more of the various types of performance tests that may be performed by conventional test systems that employ cables between the DUT and the test instrument.

FIG. 5 illustrates an exemplary test system 500 having wireless channel emulator 115 wirelessly coupled to test instrument 120 via one or more wireless communication links 505 in accordance with another exemplary embodiment of the present disclosure. The wireless coupling between wireless channel emulator 115 and test instrument 120 not only eliminates the need for interconnecting cables, but also allows the use of various types of test instruments without RF connectors. Thus, in an exemplary test configuration, both DUT 105 and test instrument 120 may be devices that lack RF connectors.

FIG. 6 shows an exemplary flowchart 600 of a method of testing a device having a beamforming circuit in accordance with an exemplary embodiment of the present disclosure.

Block 605 involves placing the MIMO antenna array in a shielded test enclosure, the MIMO antenna array being coupled to the beamforming circuitry of the DUT. This action is exemplified by placing the MIMO antenna array 111 in a shielded test enclosure 110 . The MIMO antenna array 111 is coupled to the beamforming circuit 106 of the DUT 105 .

Block 610 involves utilizing a shielded test enclosure to house the MIMO antenna array and the probe antenna array. This action is exemplified by utilizing shielded test enclosure 110 to house MIMO antenna array 111 and probe antenna array 112 located in shielded test enclosure 110 .

Block 615 involves utilizing a wireless channel simulator for a set of beam states used by the beamforming circuit to determine a set of transfer functions between the MIMO antenna array and the probe antenna array. This action is exemplified by utilizing wireless channel simulator 115 to determine a set of transfer functions between MIMO antenna array 111 and probe antenna array 112 for a set of beam states used by beamforming circuit 106 . Determining the set of transfer functions may be performed during execution of the above-described exemplary transfer function measurement procedures and/or exemplary DUT evaluation testing procedures. In one exemplary implementation, the set of beam states is the maximum number of beam states used by the beamforming circuit 106 . In an exemplary embodiment, the maximum number of beam states used by the beamforming circuit 106 corresponds to the maximum operating capacity of the beamforming circuit 106 . In another exemplary embodiment, the maximum number of beam states used by the beamforming circuit 106 may be a preselected number of beam states "B", which may be defined by a user of the test system 100, for example.

The set of transfer functions may include a time-varying transfer function F _N×K (u) between the “K” antenna elements of probe antenna array 112 and the “N” antenna elements of MIMO antenna array 111 .

Block 620 involves simulating the wireless channel simulator with the wireless channel simulator by applying one or more calibration coefficients determined by utilizing the set of transfer functions to one or more radio frequency signals propagating between the MIMO antenna array and the probe antenna array. Cableless connection between one or more antenna ports of the DUT. This action is exemplified by utilizing wireless channel emulator 115 to simulate a cableless connection by applying calibration coefficients to one or more radio frequency signals propagating between MIMO antenna array 111 and probe antenna array 112 . The one or more calibration coefficients may be applied in real-time during execution of the above-described example transfer function measurement procedures and/or the example DUT evaluation test procedures.

Block 625 involves evaluating one or more performance characteristics of the DUT using the simulated cableless connection. This action is exemplified by evaluating one or more performance characteristics of the DUT 105 using a simulated cableless connection. Some exemplary performance characteristics of the DUT 105 are downlink performance and uplink performance, such as signal characteristics and throughput.

The example flow diagram 600 may include additional steps, such as obtaining beam state information to identify the set of beam states used by the beamforming circuitry 106 in the DUT 105 to transmit test signals. Obtaining beam state information may include utilizing at least one of a known fixed beam sequence, a dynamically scheduled beam sequence with beam sequence decoding, or a dynamically scheduled beam sequence with sequence information signaled over a communication interface.

Exemplary embodiments:

Exemplary embodiments provided in accordance with the subject matter disclosed herein include, but are not limited to, the following:

1. A system comprising:

Probe antenna array;

a wireless channel emulator coupled to the probe antenna array;

A device under test (DUT) comprising:

beamforming circuitry; and

a multiple-input multiple-output (MIMO) antenna array configured to transmit one or more radio frequency signals provided by the beamforming circuit;

a shielded test enclosure that provides a cableless connection between the wireless channel emulator and one or more antenna ports of the DUT, the shielded test enclosure configured to house at least the MIMO antenna array and the probe antenna array, the probe antenna an array arranged to receive the one or more radio frequency signals transmitted by the MIMO antenna array; and

a test instrument coupled to the wireless channel emulator, the test instrument configured to evaluate the DUT based on one or more beam states utilized by the beamforming circuit to transmit the one or more radio frequency signals from the MIMO antenna array one or more performance characteristics.

2. The system of embodiment 1, wherein the beamforming circuit is one of an analog beamforming circuit, a digital beamforming circuit, or a hybrid beamforming circuit.

3. The system of embodiment 2, wherein the test instrument is configured to identify the one or more beam states by evaluating the one or more radio frequency signals received by the probe antenna array from the MIMO antenna array.

4. The system of embodiment 2, wherein the wireless channel emulator is a fading emulator that at least partially emulates a cableless connection between the wireless channel emulator and the one or more antenna ports of the DUT.

5. The system of embodiment 4, wherein the fading simulator is configured to simulate the one or more of the wireless channel simulator and the DUT by determining at least one transfer function between the MIMO antenna array and the probe antenna array This cableless connection between the antenna ports.

6. The system of embodiment 4, wherein the fading simulator is configured to simulate the cableless connection between the wireless channel simulator and one or more antenna ports of the DUT by utilizing a time-varying transfer function and a calibration matrix.

7. The system of embodiment 6, wherein the fading simulator is configured to apply the calibration matrix to the one or more radio frequency signals in real-time based on the one or more beam states used by the beamforming circuit.

8. A system comprising:

a device under test (DUT) coupled to a multiple-input multiple-output (MIMO) antenna array;

Probe antenna array;

a shielded test enclosure configured to house the MIMO antenna array and the probe antenna array; and

a wireless channel emulator coupled to the probe antenna array, the wireless channel emulator configured to at least utilize one or more beams applied to one or more radio frequency signals received by the probe antenna array from the MIMO antenna array state to emulate a cableless connection between the wireless channel emulator and one or more antenna ports of the DUT.

9. The system of embodiment 8, wherein the wireless channel emulator is further configured to simulate communication between the wireless channel emulator and the one or more antenna ports of the DUT by utilizing at least one transfer function of the shielded test enclosure. The cableless connection.

10. The system of embodiment 8, wherein the DUT includes beamforming circuitry coupled to the MIMO antenna array for transmitting the one or more radio frequency signals.

11. The system of embodiment 8, further comprising:

A test instrument is coupled to the wireless channel emulator, the test instrument configured to evaluate one or more performance characteristics of the DUT by evaluating the one or more radio frequency signals.

12. The system of embodiment 11, wherein at least one of the DUT or the test instrument is one of a personal communication device, a communication device used by a service provider, and a consumer entertainment device.

13. The system of embodiment 11, wherein the test instrument is coupled to the wireless channel emulator by utilizing one or more wireless communication links.

14. A method comprising:

placing a MIMO antenna array in a shielded test enclosure coupled to the beamforming circuitry of the device under test (DUT);

Utilize a shielded test enclosure to accommodate the MIMO antenna array and probe antenna array;

determining a set of transfer functions between the MIMO antenna array and the probe antenna array using a wireless channel simulator for a set of beam states used by the beamforming circuit;

The wireless channel simulator is simulated using the wireless channel simulator by applying one or more calibration coefficients determined using the set of transfer functions to one or more radio frequency signals propagating between the MIMO antenna array and the probe antenna array a cableless connection to one or more antenna ports of the DUT; and

One or more performance characteristics of the DUT are evaluated using the cableless connection.

15. The method of embodiment 14, wherein evaluating one or more performance characteristics of the DUT utilizing the cableless connection comprises evaluating at least one of downlink performance or uplink performance of the DUT.

16. The method of embodiment 14, wherein the one or more radio frequency signals propagating between the MIMO antenna array and the probe antenna array are test signals.

17. The method of embodiment 16, further comprising acquiring beam state information used by the DUT to transmit the test signal.

18. The method of embodiment 17, wherein obtaining beam state information comprises utilizing at least one of a known fixed beam sequence, a dynamically scheduled beam sequence with beam sequence decoding, or a dynamically scheduled beam sequence with sequence information signaled over a communication interface .

19. The method of embodiment 14, wherein the set of transfer functions comprises transfer functions between one or more ports of the MIMO antenna array and the probe antenna array.

20. The method of embodiment 14, wherein utilizing the wireless channel emulator to simulate a cableless connection between the wireless channel emulator and the one or more antenna ports of the DUT is performed in real time.

In conclusion, it should be noted that the present invention has been described with reference to a number of illustrative embodiments in order to explain the principles and concepts of the invention. From the description provided herein, those skilled in the art will understand that the present invention is not limited to these illustrative embodiments. It will be understood by those skilled in the art that many such changes may be made to the illustrative embodiments without departing from the scope of the invention.

Claims (10)

1. a kind of system comprising:

Probe antenna array (112)；

Radio channel emulator (115) is coupled to the probe antenna array (112)；

Tested device (DUT (105)) comprising:

Beamforming circuitry (106)；With

Multiple-input and multiple-output (MIMO) aerial array is configured as one that transmitting is provided by the beamforming circuitry (106) Or multiple radiofrequency signals；

It shields test shell (110), in one or more antenna ends of the radio channel emulator (115) and the DUT (105) There is provided between mouthful without cable connection, the shielding test shell (110) be configured as at least accommodating the mimo antenna array (111) and The probe antenna array (112), which is arranged to receive is emitted by the mimo antenna array (111) The one or more radiofrequency signal；With

Test equipment (120) is coupled to the radio channel emulator (115), the test equipment (120) be configured as based on by The beamforming circuitry (106) is using from the mimo antenna array (111) emitting one of the one or more radiofrequency signal Or multiple wave beam states assess one or more performance characteristics of the DUT (105).

2. the system of claim 1, wherein the beamforming circuitry (106) is analog beam wave-shaping circuit (106), digital beam One of wave-shaping circuit (106) or mixed-beam wave-shaping circuit (106).

3. the system of claim 2, wherein the test equipment (120) is configured as by assessing by the probe antenna array (112) the one or more radiofrequency signal that receives from the mimo antenna array (111) identifies the one or more wave beam State.

4. the system of claim 2, wherein the radio channel emulator (115) is decline emulator, at least partly emulate Between the radio channel emulator (115) and the one or more antenna port of the DUT (105) without cable connection.

5. the system of claim 4, wherein the decline emulator is configured as by determining the mimo antenna array (111) and being somebody's turn to do At least one transmission function between probe antenna array (112) emulates the radio channel emulator (115) and the DUT (105) this between the one or more antenna port is without cable connection.

6. a kind of system comprising:

Tested device (DUT (105)), is coupled to multiple-input and multiple-output (MIMO) aerial array；

Probe antenna array (112)；

It shields test shell (110), is configured as accommodating the mimo antenna array (111) and the probe antenna array (112)； With

Radio channel emulator (115) is coupled to the probe antenna array (112), which is matched Be set to by least be applied to by the probe antenna array (112) from the mimo antenna array (111) it is received one or One or more wave beam states of multiple radiofrequency signals emulate one of the radio channel emulator (115) and the DUT (105) Or between mutiple antennas port without cable connection.

7. the system of claim 6, wherein the radio channel emulator (115) is further configured to by being surveyed using the shielding At least one transmission function of shell (110) is tried to emulate this of the radio channel emulator (115) and the DUT (105) Or this between mutiple antennas port is without cable connection.

8. the system of claim 6, further comprising:

Test equipment (120) is coupled to the radio channel emulator (115), which is configured as by commenting The one or more radiofrequency signal is estimated to assess one or more performance characteristics of the DUT (105).

9. the system of claim 8, wherein at least one of the DUT (105) or the test equipment (120) are personal communication dresses One of communication device and consumer entertainment's device for set, being used by service provider.

10. the system of claim 8, wherein the test equipment (120), which passes through, utilizes one or more wireless communication links (505) It is coupled to the radio channel emulator (115).